The present invention is related to a network device, a communication method, and a network system.
The background arts include VXLAN (Virtual eXtension Local Area Network) technology for realizing a multi-tenant environment in which the layer 2 of approximately 16 million is disposed on the layer 3 network (see Non-patent Document 1 (IETF RFC7348 “Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks,” ISSN: 2070-1721, published in August, 2014), for example). In the technology disclosed in Non-patent Document 1, one virtual tunnel end point (VTEP) is provided for a virtual switch or the like in each physical server, and the VTEP encapsulates the layer 2 frame with a layer 3 packet, and the encapsulated packet is sent to a VTEP of the destination terminal.
In the encapsulation process, the VTEP adds a virtual network identifier (VNI: VXLAN Network Identifier) for identifying the tenants to the packet. The VTEP that received the packet performs decapsulation on the packet, identifies the transfer destination based on the destination MAC (Media Access Control) address and the VNI of the layer 2 frame inside of the packet, and transfers the packet. When not knowing the transfer destination, the VTEP discards the decapsulated packet.
The layer 2 VPN (Virtual Private Network) represented by wide area Ethernet (Ethernet is a registered trademark) improves the reliability of network by incorporating the layer 2 redundancy technology. In this network, if a Layer 2 route needs to be changed due to a failure of a physical port or the like, a device that accommodates VPN (end point) changes the layer 2 route by sending a request to other end points so that MAC address entries for the device are cleared and by clearing the entries from MAC address tables of other end points.